Known seat slide apparatuses for a vehicle are, for example, disclosed in JP2000-38063A, JP2008-279806A, and JP2005-41418A (hereinafter referred to as Patent reference 1, Patent reference 2, and Patent reference 3, respectively). The known seat slide apparatuses include lower rails and upper rails connected to the lower rails, respectively, to be movable relative to the lower rails. A lock lever, which selectively restricts the movement of the upper rail relative to the lower rail by engaging with the lower rail, is rotatably connected to the upper rail. Further, an operational lever, which is configured to transmit an operational force to the lock lever to cancel the restriction of the movement of the upper lever, is rotatably connected to the upper rail. That is, an end of the operational lever is in contact with the lock lever, and upon the rotation of the operational lever in response to the operation of the operational lever, the lock lever is pressed by the end of the operational lever, thereby canceling the restriction of the movement of the upper lever.
Further, according to the disclosures in Patent references 1 to 3, a cushioning member is provided between the operational lever and a support portion which serves as a rotational axis of the operational lever to restrain a generation of noises therebetween.
With the constructions of known seat slide apparatuses for the vehicle disclosed in Patent references 1 to 3, the looped shaped operational lever having end portions which are configured to contact the lock levers, each provided at both sides of a seat, respectively, for simultaneously unlocking the both lock levers. In those circumstances, there is a possibility that one of the end portions of the operational lever is not in contact with the lock lever because of variations when assembled, or the like. In that case, noises may be generated by a contact of the end of the lock lever which has not been in contact with the lock lever and the lock lever with an impact because of vehicle oscillation, or the like.
The generation of the noise may be restrained by providing a cushioning member between the end portion of the operational lever and the lock lever similar to the aforementioned construction between the operational lever and the support portion. However, according to this construction, the cushioning member constantly contacts an opposite member (i.e., the end of the operational lever or the lock lever) during the operation of the lock lever in response to the operation of the operational lever (i.e., when the restriction of the movement of the upper rail is canceled). Further, because the operational lever and the lock lever are not coaxially arranged, contact portions between the cushioning member and the opposite member vary in response to proceeding of the operation. That is, the cushioning member is likely to be deteriorated by constantly contacting the opposite member, and there is a risk that effects for restraining the noise may decline with time and usage. Particularly, in a case where an operational direction of the operational lever and an operational direction of the lock lever differ from each other (e.g., rotational axes of the operational lever and the lock lever are orthogonally arranged from each other), the effects for restraining the noise may drastically decline.
A need thus exists for a seat slide apparatus for a vehicle which is not susceptible to the drawback mentioned above.